Nanocrystalline and mesoporous (Ba,Sr)(Sn,Mn)O3 perovskite solid solution: a potential n-type semiconductor for room temperature ethanol sensing applications

Abstract

In this study, we report a potential n-type semiconducting nanocrystalline perovskite solid solution that is represented as (Ba,Sr)(Sn,Mn)O₃ with a specific composition of Ba_0.98Sr_0.02Sn_0.95Mn_0.05O₃ for room temperature (∼25 °C) chemo-resistive ethanol sensing application. The perovskite solid solution has been prepared using a co-precipitation route and calcined at 700 °C. XRD and SAED confirm the perovskite formation. The process of crystallisation has been confirmed through thermal analysis. FESEM analysis reveals a cubic morphology and EDS-based elemental mapping confirms the presence of all elements in their approximate ratio. Ethanol sensing shows a relatively fast sensor response (∼1.06 s) and recovery (∼1.81 s) time at room temperature and ∼55% humidity. The stable sensor response is attributed to the improvement in BET-specific surface area (∼5 m² g⁻¹), narrow slit mesopores (3.2 nm), and the core level shifts in the binding energy of O 1s as revealed by X-ray photoelectron spectroscopy (XPS). These are indicative of conducive surface-active sites for ethanol sensing. The positive slope of the Mott–Schottky plot indicates the n-type semiconducting behaviour of the synthesized perovskite solid solution.